For energy saving and carbon reduction, it is gradually the tend to inhibit the uses of incandescent light bulbs with high power consumption and progress to make full use of LED lighting fixtures with advantages of low powder consumption, power-saving, long service time and durability. However, current LED lighting fixtures are limited by the good thermal conductivity and slow heat-dissipating speed of the traditional aluminous heat-dissipating materials used. As a result, the products capable of replacing the traditional light fixtures are yet to be launched.
Moreover, as electronic products become increasingly slimmer and lighter in development, power consumption increases. If heat is not dissipated immediately when a hot spot is generated by a microscale thermal fluid during the operation of a chip, the chip cannot exhibit better performance or the consumption of the chip is increased such that the life time is lowered and the overall quality and performance are affected. Conventionally, heat dissipation on a circuit board usually involves the use of an aluminous heat-dissipating material. However, although the aluminous heat-dissipating material has a higher coefficient of thermal conductivity, its coefficient of heat dissipation is lower. As such, the aluminous heat-dissipating material has a poor heat-dissipating effect, thereby generating a thermal bottleneck.
Furthermore, thermal energy can be transferred by three approaches—conduction, convection and radiation. Solid heat-dissipating materials are mainly selected from materials with high coefficients of thermal conductivity, and dissipate heat by convection with air. Thus, the effect of heat dissipation is closely associated with the surface area of the material itself. Conventionally, heat-dissipating materials are made into spirally heat-dissipating sheets, heat-dissipating fins, spirally heat-dissipating fins, and the like, to increase the surface area for contacting air. The electronic industry gradually switches to use natural graphite, which has a loosely-packed structure and properties like lightness, high thermal conductivity and high heat dissipation, as a heat-dissipating material. However, natural graphite is not only expensive, but also bulky as compared with the volume of the conventional heat-dissipating fins. This makes natural graphite unsuitable for use in electronic products that are slimmer and lighter or LEDs. Therefore, a need still exists to research and develop heat-dissipating materials with better heat-dissipating effects.
Currently, in order to develop a suitable heat-dissipating material, TW Patent No. I307145 discloses a heat dissipater made from carbon composite containing diamond particles, an aluminum base and graphite, which can achieve good effects of thermal conduction and heat dissipation. However, the diamond particles and the aluminum base need graphite to achieve a good sealing effect with aluminum. In addition, diamonds are costly, and difficult to be processed due to a high degree of hardness. Mass production of the heat dissipater by the electronic industry is not economic.
TW Patent Application Publication No. 201114684 discloses a method for forming a powdery material and a porous material having the properties of graphite from unburned carbon. In this method, carbon-containing fly ash needs to be collected, and subjected to acid wash for purification, grinding, mixing, pressing, sintering, and secondary processing after cooling to form the graphite material. The processing steps are miscellaneous, and acid wash or alkaline wash is needed during purification. Further, the purified product needs to be grinded to 50 millimeters or lower for the mixing and pressing steps. After sintering, the product has poor planarity, as it contains metal oxides. Therefore, cutting or grinding is needed as the secondary processing for surface planarity. The process steps are too miscellaneous, and waste fluid generated by acid wash also harms the environment.
Accordingly, it is a critical issue to develop a heat-dissipating element with a simple production process and a high heat-dissipating ability, so as to resolve the issue of heat dissipation at hot spots of a heating article.